A light and scanning electron microscopy study of bone healing following inferior alveolar nerve lateralization: An experimental study in rabbits

Purpose: The purpose of this study was to evaluate the bone healing kinetics around commercially pure titanium implants following inferior alveolar nerve (IAN) lateralization in a rabbit model. Materials and Methods: Inferior alveolar nerve lateralization was performed in 16 adult female rabbits (Oryctolagus cuniculus). During the nerve lateralization procedure, 1 implant was placed through the mandibular canal, and the IAN was replaced in direct contact with the implant. During the 8-week healing period, various bone labels were administered for fluorescent microscopy analysis. The animals were euthanized by anesthesia overdose, and the mandibular blocks were exposed by sharp dissection. Nondecalcified samples were prepared for optical light and scanning electron microscopy (SEM) evaluation. Results: SEM evaluation showed bone modeling/remodeling between the IAN and implant surface. Fluorochrome area fraction labeling at different times during the healing period showed that bone apposition mainly occurred during the first 2 weeks after implantation. Conclusions: The results obtained showed that bone healing/deposition occurred between the alveolar nerves in contact with a commercially pure titanium implant. No interaction between the nerve and the implant was detected after the 8-week healing period. Appositional bone healing occurred around the nerve bundle structure, restoring the mandibular canal integrity and morphology.

Analysis of failed commercially pure titanium dental implants: A scanning electron microscopy and energy-dispersive spectrometer X-ray study

Background: the failure of osseointegration in oral rehabilitation has gained importance in current literature and in clinical practice. The integration of titanium dental implants in alveolar bone has been partly ascribed to the biocompatibility of the implant surface oxide layer. The aim of this investigation was to analyze the surface topography and composition of failed titanium dental implants in order to determine possible causes of failure.Methods: Twenty-one commercially pure titanium (cpTi) implants were retrieved from 16 patients (mean age of 50.33 +/- 11.81 years). Fourteen implants were retrieved before loading (early failures), six after loading (late failures), and one because of mandibular canal damage. The failure criterion was lack of osseointegration characterized as dental implant mobility. Two unused implants were used as a control group. All implant surfaces were examined by scanning electron microscopy (SEM) and energy-dispersive spectrometer x-ray (EDS) to element analysis. Evaluations were performed on several locations of the same implant.Results: SEM showed that the surface of all retrieved implants consisted of different degrees of organic residues, appearing mainly as dark stains. The surface topography presented as grooves and ridges along the machined surface similar to control group. Overall, foreign elements such as carbon, oxygen, sodium, calcium, silicon, and aluminum were detected in failed implants. The implants from control group presented no macroscopic contamination and clear signs of titanium.Conclusion: These preliminary results do not suggest any material-related cause for implant failures, although different element composition was assessed between failed implants and control implants.

Avaliação de diferentes métodos para sobreposições cefalométricas na maxila e mandíbula em telerradiografias em norma de 45 graus. Estudo com implantes metálicos

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Implantes curtos revisão da literatura

The contemporary implant dentistry is in constant technological development, improving the oral rehabilitation process of partial or totally edentulous patients. On the other hand, anatomical limitations, such as the maxillary sinus and the mandibular canal in the posterior region of the jaws can limit the implant placement. Furthermore, due to the absence of dental elements, alveolar ridge atrophy is frequently observed. This aspect represents a loss either in quantity or quality of the bone tissue available for the dental implant rehabilitation. To make possible the dental implant rehabilitation even in adverse conditions, some solutions have been considered, such as the use of short implants (≤ 10 mm length) and/or small diameter implants (2,8; 3,3 and 3,5 mm width). The aim of this study is to present a literature review considering the use of short implants in oral rehabilitation, presenting the currently view of the matter. Based on the literature review, the use of short implants produced similar clinical success to conventional implants (greater than 10 mm in length). Therefore, its use can be considered a viable alternative, where anatomical limitations are present.

Correlation between maxillofacial radiographic features and systemic severity as sickle cell disease severity predictor

This study was conducted to investigate the relationship among radiographic features observed on panoramic radiographs of sickle cell disease patients and analyze their relationship with history of systemic severity of the disease. Panoramic radiographs of 71 subjects with sickle cell disease were evaluated for the presence of the following radiographic bony alterations: radiopaque areas, increased spacing of bony trabeculae, horizontal arrangement of bony trabeculae and corticalization of mandibular canal. History of clinical systemic severity was assessed through direct questioning about the frequency of vaso-occlusive crisis, history of stroke, clinical jaundice, femur head necrosis, and leg ulceration. Chi-square or Fisher's exact test were applied in order to analyze possible associations between radiographic features and history of complications, with < 0.05 significance level. Increased spacing of bony trabeculae was statistically associated with absence of corticalization of mandibular canal ( < 0.01) and horizontal arrangement of bony trabeculae ( = 0.04). Statistically significant associations were demonstrated between history of clinical jaundice and presence of increased spacing of bony trabeculae ( = 0.02) and between history of stroke and presence of horizontal arrangement of bony trabeculae ( = 0.04). Based on the results of the current study, maxillofacial radiographic features may be associated with clinical parameters of systemic complications in sickle cell disease patients. The relationship between radiographic features and history of complications associated with clinical severity of sickle cell disease has not been demonstrated in the literature. Acknowledgment of such possible association may help establish prognosis and influence clinical treatment of systemic and oral complications.

Keratocystic odontogenic tumors and Carnoy's solution: results and complications assessment

Oral Diseases (2012) 18, 548557 Objective: Keratocystic odontogenic tumors (KOTs) can be treated with Carnoys solution, although this treatment modality is not free from complications. It is important to verify the incidence of complications after the use of Carnoys solution and compare these with the literature. Materials and methods: This study verified the effects of a complementary treatment for KOTs and assessed the incidence of such complications as recurrence, infection, sequestrum formation, mandibular fracture, dehiscence, and neuropathy. Results: Twenty-two KOTs treated with Carnoys solution combined with peripheral ostectomy were included, and the follow-up period varied from 12 to 78 months with a mean of 42.9 months. Complications included recurrence (4.5%), dehiscence (22.7%), infection (4.5%), and paresthesia (18.2%). No difference was found among lesions associated (9.1%) or not (0%) with nevoid basal cell carcinoma syndrome (P > 0.05). Dehiscence was influenced by marsupialization (P < 0.05), and paresthesia was observed exclusively in cases of mandibular canal fenestration (P < 0.01). Conclusions: Complementary treatment with Carnoys solution and peripheral ostectomy appear to provide efficient treatment for KOTs. Complications originating from the use of the solution are less frequent and less serious than complications associated with cryotherapy. Neuropathy seems to be related to direct contact between the solution and the epineurium.

Dentomaxillofacial manifestations of Gaucher's disease: preliminary clinical and radiographic findings

Objectives: A wide variety of manifestations is presented in patients with Gaucher's disease (GD), including bone, haematology and visceral disturbances. This study was conducted to ascertain the main maxillofacial abnormalities by means of clinical survey, panoramic and cone beam CT (CBCT); to compare the patient's group with an age-sex matched control group; and to correlate clinical and radiological data. Methods: Ten patients previously diagnosed with GD were submitted to clinical and radiological surveys (CBCT and panoramic radiographs). The examination consisted of anamnesis, extra- and intraoral examinations and analyses of each patient's records. Imaging data were collected from the point of view of 3 observers, and the results compared with a healthy group (20 individuals) by means of statistical analysis (Fisher's exact test). Results: Gaucher patients had significantly more manifestations than otherwise healthy carriers. The most prevalent findings were enlarged marrow spaces, generalized osteopenia and effacement of jaw structures (mandibular canal, lamina dura and mental foramen). Here we describe a case in which thickening of the maxillary sinus mucosa was observed on CBCT rather than opacification of the sinus as seen on panoramic radiographs. Pathological fractures, root resorption and delay on tooth eruption were not observed. Conclusions: A poor relationship could be observed between clinical and radiological data. Patients showed important bone manifestations, which require careful diagnostic and surgical planning whenever necessary. Although panoramic radiographs have shown significant differences, CBCT is more effective in pointing out differences between patients and a control group, thus showing it as an important tool for evaluation of Gaucher patients. Dentomaxillofacial Radiology (2012) 41, 541-547. doi: 10.1259/dmfr/143023353

Bone dimensions in the posterior mandible: a retrospective radiographic study using cone beam computed tomography. Part 1--analysis of dentate sites

This retrospective radiographic study analyzed the dimensions of the alveolar bone in the posterior dentate mandible based on cone beam computed tomography (CBCT) images. A total of 56 CBCT images met the inclusion criteria, resulting in a sample size of 122 cross sections showing posterior mandibular teeth (premolars and molars). The thickness of the buccal and lingual bone walls was measured at two locations: 4 mm apical to the cementoenamel junction (measurement point 1, MP1) and at the middle of the root (measurement point 2, MP2). Further, alveolar bone width was assessed at the level of the most coronal buccal bone detectable (alveolar bone width 1, BW1) and at the superior border of the mandibular canal (alveolar bone width 2, BW2). The vertical distance between the two as well as the presence of a lingual undercut were also analyzed. There was a steady increase in buccal bone wall thickness from the first premolar to the second molar at both MP1 and MP2. BW1 at the level of the premolars was significantly thinner than that for molars. Alveolar bone height was constant for all teeth examined. For the selection of an appropriate postextraction treatment approach, analysis of the alveolar bone dimensions at the tooth to be extracted by means of CBCT can offer valuable information concerning bone volume and morphology at the future implant site.

[The mental foramen or "the crossroads of the mandible." An anatomic and clinical observation]

This paper presents a clinical and anatomical review of the mental foramen (MF) based on recent publications (since 1990). Usually, the MF is located below the 2nd premolar or between the two premolars, but it may also be positioned below the 1st premolar or below the mesial root of the 1st molar. At the level of the MF, lingual canals may join the mandibular canal (hence the term "crossroads"). Accessory MF are frequently described in the literature with large ethnic variations in incidence. The emergence pattern of the mental canal usually has an upward and posterior direction. The presence and extent of an "anterior loop" of the mental canal may be overestimated with panoramic radiography. Limited cone-beam computed tomography currently appears to be the most precise radiographic technique for assessment of the "anterior loop". The mental nerve exiting the MF usually has three to four branches for innervation of the soft tissues of the chin, lower lip, facial gingiva and mucosa in the anterior mandible. The clinician is advised to observe a safety distance when performing incisions and osteotomies in the vicinity of the MF.

Bone dimensions in the posterior mandible: a retrospective radiographic study using cone beam computed tomography. Part 2- analysis of edentulous sites.

A precise radiographic evaluation of the local bone dimensions and morphology is important for preoperative planning of implant placement. The purpose of this retrospective study was to analyze dimensions and morphology of edentulous sites in the posterior mandible using cone beam computed tomography (CBCT) images. This retrospective radiographic study measured the bone width (BW) of the mandible at three locations on CBCT scans for premolars (PM1, PM2) and molars (M1, M2): at 1 mm and 4 mm below the most cranial point of the alveolar crest (BW1, BW2) and at the superior border of the mandibular canal (BW3). Furthermore, the height (H) of the alveolar process (distance between the measuring points BW1 and BW3), as well as the presence of lingual undercuts, were analyzed. A total of 56 CBCTs met the inclusion criteria, resulting in a sample size of 127 cross sections. There was a statistically significant increase from PM1 to M2 for the BW2 (P < .001), which was not present for BW1 and BW3 values. For the height of the alveolar process, the values exhibited a decrease from PM1 to M2 sites. Sex was a statistically significant parameter for H (P = .001) and for BW1 (P = .03). Age was not a statistically significant parameter for bone width (BW1: P = .37; BW2: P = .31; BW3: P = .51) or for the height of the alveolar process (P = .41) in the posterior mandible. Overall, 73 (57.5%) edentulous sites were evaluated to be without visible lingual undercuts; 13 (10.2%) sites exhibited lingual undercuts classified as influential for implant placement. Precise evaluation of the alveolar crest by cross-sectional imaging is of great value to analyze vertical and buccolingual bone dimensions in different locations in the posterior mandible. In addition, CBCTs are valuable to diagnosing the presence of and potential problems caused by lingual undercuts prior to implant placement.

A new Eocene archaeocete (Mammalia, Cetacea) from India and the time of origin of whales

Himalayacetus subathuensis is a new pakicetid archaeocete from the Subathu Formation of northern India. The type dentary has a small mandibular canal indicating a lack of auditory specializations seen in more advanced cetaceans, and it has Pakicetus-like molar teeth suggesting that it fed on fish. Himalayacetus is significant because it is the oldest archaeocete known and because it was found in marine strata associated with a marine fauna. Himalayacetus extends the fossil record of whales about 3.5 million years back in geological time, to the middle part of the early Eocene [≈53.5 million years ago (Ma)]. Oxygen in the tooth-enamel phosphate has an isotopic composition intermediate between values reported for freshwater and marine archaeocetes, indicating that Himalayacetus probably spent some time in both environments. When the temporal range of Archaeoceti is calibrated radiometrically, comparison of likelihoods constrains the time of origin of Archaeoceti and hence Cetacea to about 54–55 Ma (beginning of the Eocene), whereas their divergence from extant Artiodactyla may have been as early as 64–65 Ma (beginning of the Cenozoic).

IN VITRO INCIDENCE of ROOT CANAL BIFURCATION IN MANDIBULAR INCISORS BY RADIOVISIOGRAPHY

Objective: The aim of this study was to verify, in vivo and in vitro, the prevalence of root canal bifurcation in mandibular incisors by digital radiography. Material and Methods: Four hundred teeth were analyzed for the in vivo study. Digital radiographs were taken in an orthoradial direction from the mandibular incisor and canine regions. The digital radiographs of the canine region allowed visualizing the incisors in a distoradial direction using 20 degrees deviation. All individuals agreed to participate by signing an informed consent form. The in vitro study was conducted on 200 mandibular incisors positioned on a model, simulating the mandibular dental arch. Digital radiographs were taken from the mandibular incisors in both buccolingual and mesiodistal directions. Results: The digital radiography showed presence of bifurcation in 20% of teeth evaluated in vitro in the mesiodistal direction. In the buccolingual direction, 17.5% of teeth evaluated in vivo and 15% evaluated in vitro presented bifurcation or characteristics indicating bifurcation. Conclusions: Digital radiography associated with X-ray beam distally allowed detection of a larger number of cases of bifurcated root canals or characteristics of bifurcation.

Comparative analysis of three rotary instruments used for coronal pre-enlargement in radicular dentin thickness and root canal area of mandibular molars

Purpose: The purpose of this study was to evaluate the increase of the cervical area and dentin thickness in mesial and distal walls of the mesial canals from mandibular molars after the use of LA Axxess (LA), CP Drill (CP) and Gates-Glidden (GG) rotary instruments. Material and Methods: Sixty root canals from thirty mandibular first molar were sectioned 3 mm below the cement-enamel junction, divided in 3 groups (n = 20 root canals, each) according to rotary instrument used, and the cervical images were captured before and after pre-enlargement instrumentation. The increase of the instrumented cervical area (mm2) and the dentin removal thickness (mm), at mesial and distal walls were calculated using Image tools software, by comparison of images. Data were analyzed by ANOVA and Tukey tests (p=0.05). Results: All rotary instruments promoted thickness reduction in dentin walls. In mesial wall, all rotary instruments promoted similar thickness reduction of dentinal wall and did not differ from each other (p>0.05). In distal wall, LA Axxess instrument promoted higher dentin thickness reduction than other groups (p<0.05). The three rotary instruments promoted different increase at the instrumented cervical area (p<0.05), LA promoted the highest increase area and GG and CP presented similar results. Conclusion: LA 20/0.06 promoted the highest thickness reduction in distal wall and increase of cervical area of root canal. On the other hand, CP was the safest instrument, with lower dentin removal of distal wall and similar increased area to GG.

Resultate und ausser- gewöhnliche Komplikationen der Chirurgie der Gehörgangexostosen [Results and extraordinary complications of surgery for exostoses of the external auditory canal].

We present a retrospective study on 22 operations of exostosis of the external auditory canal in 20 patients. 8 patients were passionated by water sports. The most frequent indication for surgery (13 operations) was recurrent external otitis or ceruminal obstruction. In 7 cases the need for a wider access to the middle ear indicated surgery. Surgery was usually performed as an outpatient procedure, maximum hospitalization was 3 days. The mean healing period was 6 (3-10) weeks. Mean follow up was 43 (3-110) months. There were no severe intraoperative complications such as facial paresis, lesions of the ossicles or of the inner ear. As intraoperative complications we found 2 perforations of the tympanic membrane, 2 expositions of the capsule of the mandibular joint, one of which was followed by chronic pain. As postoperative complications we found an early soft tissue stenosis of the external auditory canal and one late soft tissue stenosis which recurred after revision surgery. No recurrence of exostosis was seen. We describe an up to now unknown complication: the appearance of bilateral petrositis caused by staphylococcus epidermidis after bilateral surgery in an otherwise healthy patient. This study confirms that severe complications are rare, minor ones however relatively common. And that also minor complications may have a troublesome follow. Therefore and because of the potential of severe complications indication for surgery must be made cautiously and risks of the operation must not be underestimated.

Efficacy of NiTi rotary instruments in removing calcium hydroxide dressing residues from root canal walls

The aim of this study was to evaluate the efficacy of three rotary instrument systems (K3, ProTaper and Twisted File) in removing calcium hydroxide residues from root canal walls. Thirty-four human mandibular incisors were instrumented with the ProTaper System up to the F2 instrument, irrigated with 2.5% NaOCl followed by 17% EDTA, and filled with a calcium hydroxide intracanal dressing. After 7 days, the calcium hydroxide dressing was removed using the following rotary instruments: G1 - NiTi size 25, 0.06 taper, of the K3 System; G2 - NiTi F2, of the ProTaper System; or G3 - NiTi size 25, 0.06 taper, of the Twisted File System. The teeth were longitudinally grooved on the buccal and lingual root surfaces, split along their long axis, and their apical and cervical canal thirds were evaluated by SEM (×1000). The images were scored and the data were statistically analyzed using the Kruskall Wallis test. None of the instruments removed the calcium hydroxide dressing completely, either in the apical or cervical thirds, and no significant differences were observed among the rotary instruments tested (p > 0.05).